package buke;

import java.util.Scanner;

public class L {
 public static int uniquePaths (int m,int n) {
	 int[][] f= new int[m][n];
	 for(int i = 0;i<m;i++) {
		 f[i][0] = 1;
	 }
	 for(int j = 0;j<n;j++) {
		 f[0][j] = 1;
	 }
	 for(int i = 1;i<m;i++) {
		 for(int j=1;j<n;j++) {
			 f[i][j] = f[i-1][j]+f[i][j-1];
			 
		 }
	 }
	 return f[m-1][n-1];
 }
 public static void main(String[] args) {
	Scanner c = new Scanner(System.in);
	int m = c.nextInt();
	int n = c.nextInt();
	int a = uniquePaths(m,n);
	System.out.println(a);
}
}
